chunk loader issue fixes, and a couple others

Fix: Handle ChunkLoading issues by persisting them directly in ForgeChunkManager (ChunkLoaders will need to be "visited" one time so that they are persisted properly).
Fix Railcraft tanks #816 
Fix Xycraft soil #814 (Water works correctly as far as I can tell)
Fix: Difficulty setting is set for new Mystcraft dimensions
Unconfirmed fix: IC2 spam #796 
Fix: Thaumcraft and Soulshards drop XP #785 
Fix: dupe bug on player death.
Fix: portal traversal sticking player in ground (Portal Mod)
Fix: Worlds should unload if no chunks are loaded

Performance:
Added Naller's EntityItem.onUpdate logic (less jerky than Spigot's version and faster item combining)
Moved persistent chunks into World to reduce hash lookups in updateEntities (for @nallar)
LoadChunkOnProvide calls isolated to method calls on World (for @nallar to patch with TT easier)
Added delay to chunk cleanup on server start (prevent chunk thrashing on restarts)
Does not add forced chunks to chunksToUnload (since Spigot keys off that for skipping ticks)
Disable "[playername] moved wrongly" messages if the player just teleported
Ignore "Attempted to place a tile entity where there was no entity tile" messages if the chunk is not loaded yet (some mods do this on purpose -- I'm looking at you xycraft...)

Other:
Added log message to help isolate #838 (although this is fixed in a later Factorization release)
Put try/catch around Forge Event publish (Mods shouldn't bring down the server should they?)